A resistive change type memory that utilizes a change in element resistance controlled by a current has recently been proposed as a candidate for a large capacitance, high-speed operable memory device equivalent to a dynamic random access memory (DRAM). A 1T/1R type device is an example of the resistive change type memory. In this case, it is the most serious problem how much current can be run from a transistor into a resistive element within a predetermined area.
Further, when a MOSFET is used as a cell transistor, if the cell area is reduced, the contact area becomes small relative to the source and drain electrodes. An increase in the so-called parasitic resistance (contact resistance) of the contact area may well cause significant degradation of current driving. Further, since in the 1T/1R type device, a certain resistor is connected to one of the source and drain electrodes of the MOSFET, it will function as another parasitic resistance.